Protective device for a hand machine tool

ABSTRACT

A guard device for a hand power tool, in the form of a sanding/grinding hand power tool, has a wheel guard enclosing at least part of a rotating tool in a radial direction; a guide for guiding the wheel guard along a work piece, and comprising a fastening device for mounting the wheel guard on the hand power tool, wherein the guide is joined with the wheel guard in torsion-resistant fashion, and the wheel guard is mounted in a fashion that allows it to move relative to the fastening device; and a depth-of-cut stop limiting the relative movement of the wheel guard and fastening device, and being lockable in position with positive engagement in preselected stepped positions.

BACKGROUND OF THE INVENTION

The invention is based on a guard device for a hand power tool, inparticular for a sanding/grinding hand power tool, according to thepreamble of claim 1.

Guard devices for hand power tools, in particular for angle grinders,are known, the wheel guards of which offer a certain level of protectionduring sanding/grinding work, but which do not support a sufficientlevel of dust removal. This is due to the fact that, during operationand in the idle position, the wheel guard covers only part of the sideof the tool and, in particular, a sanding disc/grinding wheel of thehand power tool. The removal of sanding/grinding dust using vacuum istherefore only slightly effective, despite the powerful external vacuumcleaners that are typically used

ADVANTAGES OF THE INVENTION

The invention is based on a guard device for a hand power tool, inparticular for a sanding/grinding hand power tool, comprising a wheelguard that is provided to enclose at least part of a rotating tool inthe radial direction, and comprising a guide means for guiding the wheelguard along a work piece, as well as a fastening device for mounting thewheel guard on the hand power tool.

It is proposed that the guide means are joined with the wheel guard intorsion-resistant fashion, and the wheel guard is mounted in a fashionthat allows it to move relative to the fastening device.

With a guard device of this type, a tool of a hand power tool, inparticular a sanding/grinding hand power tool, can be enclosed by thewheel guard completely or to a predetermined extent, and, in fact,independent of the tool position relative to a work piece. As a resultof this, an operator is protected to a large extent from particles thatare removed from a work piece by the tool, i.e., sanding/grinding dustin particular. Additionally, sanding/grinding dust removal can bemanaged particularly effectively and, in most cases, neither an internalventilator nor an external vacuum cleaner is required to remove dust.Due to the fact that the wheel guard is mounted in a fashion that allowsit to move relative to the fastening device, the wheel guard is alsomounted in a fashion that allows it to move relative to the toolposition. As a result, the wheel guard can always lie on the work piecewhile the hand power tool is being operated, regardless of how far thetool enters the work piece. The guide means, which are interconnectedwith the wheel guard in torsion-resistant fashion, thereby guides thewheel guard along the work piece, by way of which it is ensured that thewheel guard bears against the work piece during operation without beingable to tilt relative to the guide means. The wheel guard can thereforebe held in a position that is constant relative to the surface of thework piece, independent of the depth of penetration of the tool in thework piece. Particles can therefore effectively be prevented fromescaping from between the wheel guard and the surface of the work piece.

The invention is capable of being used particularly advantageously witha wheel guard for an angle grinder, since an angle grinder is used inmobile fashion and in various positions, e.g., in an overhead position.When the tool is completely enclosed or enclosed to a predeterminedextent by the wheel guard, the operator is protected to a large extentfrom sanding/grinding dust.

The wheel guard encloses the tool in essential regions and, inparticular, at least partially in the radial direction. In the case of adisc-shaped, rotating tool, at least one segment of the arc of theperiphery of the tool is completely enclosed in the radial direction.Particles of the work piece being worked thrown off by the tool, such assanding/grinding dust, are therefore captured by the wheel guard in theregion in which it encloses the tool in the radial direction.Advantageously, the wheel guard encloses at least 120°, in particular atleast 180° of the periphery of the tool, in order to capture as muchdust as possible.

In an advantageous embodiment of the invention, the guide means compriseat least one sliding shoe. The wheel guard can be guided safely on thework piece on a sliding shoe that extends advantageously in the workingdirection of the tool. When the sliding shoe is designed with a flatbearing surface or bearing edge, the wheel guard is guided particularlysafely over a flat work piece. By minimizing the guide means on a glideshoe that is seated tightly on the wheel guard, the wheel guard can beproduced in a particularly lightweight and weight-saving fashion.

A particularly simple mounting of the wheel guard in a fashion thatallows it to move relative to the fastening device is obtained bymounting the wheel guard in a fashion that allows it to swivel relativeto the fastening device. The two elements can be interconnected at onecenter of rotation.

A particularly good level of sanding/grinding dust removal can beachieved when the wheel guard—in a state in which it lies on a flat workpiece in the operating position—is provided to enclose the tool togetherwith the work piece to an extent that does not depend on the depth ofpenetration of the tool in the work piece. The work piece can beenclosed entirely or to a predetermined extent, so that, when the toolis pulled out of the work piece, for example, no dust or no additionaldust leaves the wheel guard and enters the surroundings.

Advantageously, an air-intake opening remains in the wheel guard orbetween the wheel guard and the work piece, the size of which isindependent of the depth of penetration of the tool in the work piece.In this fashion, a constant flow of air—that is independent of the depthof penetration of the tool in the work piece—from the air-intake openingto a dust removal tube, and, therefore, constant dust removal, is madepossible.

In a preferred embodiment of the invention, the guard device comprises aspring mechanism that presses the wheel guard against a work pieceduring operation. The wheel guard therefore lies on the work piece viathe guide means, so that an undesired slit does not form between thewheel guard and the work piece through which the dust is carried out ofthe wheel guard.

A guard device, the wheel guard of which encloses the tool completely inthe axial direction in the idle position, ensures a high level of worksafety: an operator is protected effectively against injury caused bythe tool. This also applies for a guard device, in the case of which thetool retracts completely into the wheel guard when it exits the workpiece. Additionally, such a guard device ensures good protection againstthe release of sanding/grinding dust or particles. The dust rotatingwith the tool is drawn into the wheel guard along with the toolretracting into the wheel guard.

The wheel guard advantageously encloses two units that are movablerelative to each other that, in mutual interplay, comprise an operatingposition and a tool replacement position, whereby at least one of theunits, in the tool replacement position, exposes the tool in the axialdirection to an extent that allows a tool to be replaced. With such anembodiment of the wheel guard, easy tool replacement is possible despitethe fact that the tool is largely enclosed in the idle position. Adesign for this that is particularly simple is obtained by the fact thatthe two units are capable of being swiveled independently of each otheraround a common center of rotation relative to the fastening device. Thetwo units are connected to the fastening device with a rivet or screw,for example. One of the units is a pivoted cover plate, for example. Thearrangement of the pivoted cover plate to cover the axial side of thesanding disc/grinding wheel improves the work safety with the hand powertool and prevents sanding/grinding dust from escaping from the side,which makes it possible to replace the tool more quickly by swivelingthe pivoted cover plate around a center of rotation. The pivoted coverplate can be closed particularly reliably and it is easy to open bymeans of the positive fastening system of the pivoted cover plate withlobes and snap-in tongues that snap in place together.

A further advantage is achieved in that the wheel guard comprises awindow that allows an operator to see the tool and, in particular, onthe side of the tool closest to a work piece. This makes it possible tocontrol the position of the tool in the work piece particularly easilyand effectively.

Advantageously, the wheel guard comprises an observation slit. It can beformed by means of an opening in the wheel guard, for example, or bymeans of a slant in a part of the wheel guard. The observation slitoriented toward the narrow side of the sanding disc/grinding wheelensures a more controlled handling of the angle grinder with the wheelguard, mainly for exact placement of the sanding disc/grinding wheel inmortar joints. Visual control of the tool is particularly enhanced bymeans of the window in combination with an observation slit. Theair-intake opening can be used as an observation slit. The air drawn inthrough the observation slit causes turbulence that essentially keepsthe window free from dust. When the dust is removed from the oppositeside of the window, e.g., by a dust removal tube located there, the airturbulence keeps the window essentially free from dust.

The guard device preferably comprises a dust removal tube, e.g., forconnection to a dust removal device. Particles can be removed from thewheel guard particularly effectively through a dust removal tube. Whenthe dust removal tube is mounted on the wheel guard, the dust removaltube is moved with the wheel guard. The dust removal tube is thereforein a constant position relative to the work piece, by way of whichparticularly good dust removal is possible.

The blow-off effect of the sanding/grinding dust is further improved bymeans of a damping plate located inside the wheel guard, since the airwhirled by the rotating sanding disc/grinding wheel backs up there, andthe air stream is directed out to the dust removal tube. The dampingplate can be located on the side opposite the dust removal tube and itbe integrally molded on the wheel guard, for example.

Depth-of-cut can be preselected particularly quickly by means of adepth-of-cut stop that snaps into place with positive engagement bypressing, sliding, or releasing the push button, and a preselectedsetting cannot be selected accidentally.

SUMMARY OF THE DRAWINGS

Further advantages result from the following description of thedrawings. An exemplary embodiment of the invention is presented in thedrawings. The drawings, the description, and the claims contain numerousfeatures in combination. One skilled in the art will advantageouslyconsider them individually as well and combine them into reasonablefurther combinations.

FIG. 1 is a top view of a hand power tool having a guard deviceaccording to the invention, in the working position,

FIG. 2 is a view of the hand power tool in FIG. 1 from above,

FIG. 3 is a view of the hand power tool in FIG. 1 from the oppositeside,

FIG. 4 is the view according to FIG. 3 rotated by 90° around thevertical axis,

FIG. 5 is the view according to FIG. 1 in the idle position,

FIG. 6 is the view according to FIG. 5 from the opposite side,

FIG. 7 is the side view of a further exemplary embodiment of a handpower tool having a guard device according to the invention, in the idleposition,

FIG. 8 is the view according to FIG. 7 from the opposite side,

FIG. 9 is the view according to FIG. 8 rotated 90° around thelongitudinal axis,

FIG. 10 is the view according to FIG. 7 in the working position,

FIG. 11 is a detailed view of the dust removal tube according to FIGS. 7and 10,

FIG. 12 is a spatial representation according to FIG. 1,

FIG. 13 is a spatial view from below according to FIGS. 1 and 2,

FIG. 14 is a view of the adjustable stop for limiting the depth of cut,

FIG. 15 is a detailed view of the depth-of-cut stop,

FIG. 16 shows a section of the pivoted cover plate,

FIG. 17 is a bottom view of the angle grinder wheel guard according toFIG. 1,

FIG. 18 shows a side shell of the wheel guard as seen from the outside,

FIG. 19 shows the housing shell according to FIG. 18 as seen from theinside,

FIG. 20 is a spatial representation of the anterior region of thesanding/grinding machine comprising dust removal tube extending at aslant relative to the sanding tool.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is the side view of an angle grinder 20, the motor housing 22 ofwhich extends substantially upward at a right angle and contains anot-shown motor.

As viewed downward at a right angle, a gearbox housing 24 adjoins themotor housing 22, the driven shaft 26 (FIG. 13) of which said gearboxhousing extends at a right angle to the plane of the drawing and has atool mounted on its exposed end. The tool is a sanding disc/grindingwheel 28. It rotates in the direction of rotation 29 in the clockwisedirection and plunges into a work piece 30, in which it cuts a groove 32coming from the right.

As shown on the left side, a sliding button 34 of an on-and-off switchis mounted on the motor housing 22.

A guard device 33 is mounted on the angle grinder 20. It comprises afastening device and a wheel guard 40. The fastening device is designedas a swiveling arm 38. The swiveling arm 38 is mounted via awell-fitting mounting opening 36 (FIG. 18) on a cylindrically-shaped,axial extension of the gearbox housing 24, i.e., the neck 25. Theswiveling arm 38, in turn, is mounted on the wheel guard 40 and iscapable of being swiveled upward and downward around a center ofrotation 42 relative to the wheel guard 40. The swiveling arm 38 and thewheel guard 40 are reliably guided in opposition to each other by meansof a guide bolt 46 seated on the wheel guard 40 in a guide slot 44 ofthe swiveling arm 38. As shown on the left side, the swiveling arm 38has a knob 48 mounted on it, by way of which the angle grinder 20 withthe wheel guard 40 can be guided on a work piece 30. Additionally, theknob 48 is grasped to manually adjust the depth of cut, whereby theswiveling arm 38 can be adjusted upward and downward. The wheel guard 40is seated on the work piece 30 with a guide means, i.e., a rail 50designed in the shape of a runner, located on its bottom side. The guidemeans ensures that the wheel guard 40 remains perpendicular to thesurface of the work piece.

As shown on the bottom left, the wheel guard 40 has a dust removal tube52 mounted on it directly adjacent to the rail 50. Dust created duringsanding is removed through said dust removal tube, e.g., via an insertedtube piece and a dust suctioning device attached thereto. The dustremoval tube 52 is situated at a 45° angle relative to the axis ofrotation of the sanding disc/grinding wheel 28.

As shown on the bottom right, the wheel guard 40 is angled at a slant inthe upward direction, so that an observation opening 54 is formed,through which the tool operator can control the engagement of thesanding disc/grinding wheel 28 in the work piece 30 and/or the groove32. As shown at the top right, a handle 56 projects out of the wheelguard 40 at an angle, by way of which the unit comprising angle grinder20 and wheel guard 40 can be comfortably guided along the work piece 30.

A spring mechanism is located between the swiveling arm 38 and the wheelguard 40 at the center of rotation 42. The spring mechanism comprises apreloaded leg spring 58 that tries to press the swiveling arm 38 upward.As a result, the angle grinder 20 must be moved relative to the wheelguard 40 according to FIG. 1 in a counterclockwise direction against thespring force of the leg spring 58 in order to reach its working positionin which the sanding disc/grinding wheel 28 protrudes downward out ofthe pass-through slot 73 (FIG. 17) and/or past the rail 50 so that itcan penetrate the work piece 30.

If the angle grinder 20 with the wheel guard 40 is lifted off of thework piece 30, the leg spring 58 pulls the wheel guard 40 downwardrelative to the swiveling arm 38, so that the sanding disc/grindingwheel 28 disappears completely inside the wheel guard 40.

The usual method of working with the angle grinder 20 is directed in theadvancing direction 57, so that the movement of the work piece 30relative to the sanding disc/grinding wheel 28 is opposite to thedirection of rotation 29 of the sanding disc/grinding wheel 28.

The view from the top shown in FIG. 2 shows the slanted arrangement ofthe handle 56 on the wheel guard 40, and the slanted extension of thedust removal tube 52. Moreover, the neck 25 of the gearbox housing 24 isshown, which said neck engages in the mounting opening 36 of theswiveling arm 38.

FIG. 3 shows the angle grinder 20 with wheel guard 40 according to FIG.1 from the opposite side, also in the working position, with the sandingdisc/grinding wheel 28 protruding far downward. A guide rule 60 is shownin FIG. 3, on which the knob 48 is guided and which can be locked inposition by rotating it around its longitudinal axis. Furthermore, adepth-of-cut stop 62 is shown below the knob 48, which said depth-of-cutstop is also capable of being displaced in the guide rule 60 and whichis capable of being locked in position with positive engagement inpreselected, stepped positions by the press of a button. Thedepth-of-cut stop 62 is captively secured on the guide rule 60 (FIGS.14, 15).

The guard device 33 comprises two units capable of being moved oppositeto one another, i.e., the wheel guard 40 and a pivoted cover plate 64.The pivoted cover plate 64 is located on the opposite side of theswiveling arm 38 and is intended to cover the sanding disc/grindingwheel 68. The pivoted cover plate 64 is capable of being swiveledtogether with the wheel guard 40 around the center of rotation 42. Toreplace the sanding disc/grinding wheel 28, the pivoted cover plate 64is swiveled toward the upper left—as viewed in this drawing—from theoperating position into a tool replacement position. In this outwardlyswiveled tool replacement position, the exposed end of the driven shaft26 and/or the retaining nut 27 (FIG. 13) are easily accessible, so that,after the retaining nut 27 is loosened, the sanding disc/grinding wheel28 can be removed in the axial direction out of the plane of thedrawing.

In its lower region, the pivoted cover plate 64 comprises a window 66 ina rectangular opening. Located between the window 66 and the rail 50 isa lateral air-intake opening 68 through which air can pass that replacesthe air blown out by the rotating sanding disc/grinding wheel 28 toremove sanding/grinding dust. Relative to the sanding disc/grindingwheel 28, the air-intake opening 68 is located opposite from the dustremoval tube 52. In a state lying on the flat work piece 30 in theoperating position, the air-intake opening 68 has a size that does notdepend on the depth of penetration of the sanding disc/grinding wheel 68in the work piece 30, since the rail 50—which, together with the wheelguard 40, borders the air-intake opening 68—always lies flat on the workpiece 30 independent of the depth of penetration of the sandingdisc/grinding wheel 28 in the work piece 30.

The window 66 is inserted in frame segments 70 fastened to the pivotedcover plate 64, and it engages with the pivoted cover plate 64 incaptive fashion with a snap-in tongue 72 extending above it.

FIG. 4 shows a side view, rotated by 90°, of the angle grinder 20according to FIG. 3, whereby, in contrast to the preceding figures, thedesign of the guide rule 60 comprising a central slot 61—for swivelingthe knob 48 vertically and/or for moving the depth-of-cut stop 62 withits push button 63—is shown. The sanding disc/grinding wheel 28 is alsoshown penetrating the groove 32, which said groove is designed as amortar joint. The rest of the details explained hereinabove are labelledwith reference numerals but will not be explained once more.

FIG. 5 shows the angle grinder 20 according to FIG. 1 with the wheelguard 40 in the idle position, in which the sanding disc/grinding wheel28 has disappeared inside the wheel guard 40, because the swiveling arm38 has been moved upward relative to the wheel guard 40. This is madeparticularly clear when the relative position of the guide bolt 46 tothe guide slot 44 according to FIG. 5 is compared with said relativeposition of the guide bolt to the guide slot in FIG. 1.

FIG. 6 shows how the sanding disc/grinding wheel 28—located behind therail 50—is, positioned within the contour of the wheel guard 40.

In FIGS. 5 and 6, the idle position of the wheel guard 40 isrecognizable by the fact that the knob 48—as viewed here—is seatedagainst the upper stop of the guide rule 60.

FIGS. 7 and 8 show an exemplary embodiment that is slightly modified ascompared with FIGS. 1 through 6, comprising a guard device 133, in thecase of which a dust removal tube 152 projecting out of the wheel guard140 at a right angle is provided, which said dust removal tube isprovided for suctioning purposes using a separate vacuum cleaner.Moreover, an elongated, stem-like handle 156 is attached directly to theangle grinder 120 in order to make two-handed operation of the anglegrinder 120 possible, whereby one hand can grasp the handle 156, and theother hand can grasp the motor housing 122. Moreover, the swiveling arm138 is provided with a knurled nut 148 instead of a knob, with whichsaid knurled nut the preselected depth of cut can be adjusted.

Located on the underside of the wheel guard 140 is a rail 150 forguidance on a work piece 30 shown in FIG. 10.

FIG. 8 shows the view according to FIG. 7 from the opposite side,whereby, in contrast to FIG. 3 of the first exemplary embodiment, thewindow 166 is capable of being secured by means of a knurled nut.

FIGS. 7 and 8 show the angle grinder 120 with the wheel guard 140 in theidle position, i.e., with the sanding disc/grinding wheel 28 drawn intothe wheel guard 140, while FIGS. 9 and 10 show the same angle grinder120 in the working position, i.e., with the sanding disc/grinding wheel28 protruding below the rail 150.

FIG. 9 clearly shows a collet 123 that clamps a collar of the wheelguard 140 tightly against the neck 125 of the angle grinder 120. Thewheel guard 140 is easy to remove by loosening a hexagon bolt andopening the collet 123 away from the neck 125 of the angle grinder 120if the sanding disc/grinding wheel 28 was previously removed. Also shownare the knurled nut 167 for holding the pivoted cover plate 164 inposition against the wheel guard 140, the knurled nut 148 for settingand releasing the preselected depth of cut, and the depth-of-cut stopcapable of being adjusted using the knurled nut 162.

FIG. 9 clearly shows the leg spring 158, with which the angle grinder120 is automatically moved relative to the wheel guard 140 around thecenter of rotation 142 into the idle position. Also shown is a suctiontube 151 for connection to a vacuum cleaner, with which thesanding/grinding dust can be effectively removed.

FIG. 10 shows the angle grinder 120 in the working position, wherebysanding/grinding dust is thrown in the direction of rotation 29 of thesanding disc/grinding wheel 28 tangentially from the point where thesanding disc/grinding wheel 28 exits the work piece 30 and against theinterior wall of the dust removal tube 152, and from there, it iscapable of being suctioned off easily via the suction tube 151.

FIG. 11 shows a detained view of the dust removal tube 152 in itsposition relative to the sanding disc/grinding wheel 28. One can seethat the radially outermost region of the sanding disc/grinding wheel 28extends into an opening 174 of the dust removal tube 152. Part of thedust removal tube 152 therefore penetrates the planes—imagined tocontinue endlessly—of the two flat sides of the sanding disc/grindingwheel 28. The opening 174 is designed in such a fashion that part of thedust removal tube 152 reaches behind the sanding disc/grinding wheel 28.The opening 174 is therefore designed in the shape of a slot.

The conveying air stream produced by the sanding disc/grinding wheel28—together with dust particles—meets the bent surface of the part ofthe dust removal tube 152 that penetrates the planes of the two flatsides of the sanding disc/grinding wheel 28, as indicated by the arrows.The conveying air stream with the sanding/grinding dust meeting thisimpact surface at a high rate of speed is further directed into the dustremoval tube 152 in such a fashion that it executes a cyclone-likevortex motion in the dust removal tube. The conveying air and duststream set into rotational motion in this fashion has sufficient kineticenergy to exit the dust removal tube 152 on its side furthest from theangle grinder 20 under its own power. A vacuum cleaner can be installeddownstream for safety reasons, however, to prevent the dust removal tube152 from becoming blocked in certain working positions of the anglegrinder 120.

FIG. 12 shows a side view of a further exemplary embodiment, the designof which essentially matches that of the angle grinder 20 shown in FIGS.1 through 4. The only differences are that the stem-like handle 56 isscrewed directly onto the gearbox housing 24 of the angle grinder 20,and the knob is missing. The collet 23 and the locking screw that holdthe angle grinder 20 tightly in position relative to the wheel guard 40are particularly easy to see.

FIG. 13 shows a spatial representation nearly parallel to the sandingdisc/grinding wheel 28 from the underside of the wheel guard 40. Theembodiment of the rail 50 with a glide shoe 49 is shown particularlyclearly. The rail 50 is located in the exit region of the wheel guard40, where part of the sanding disc/grinding wheel exits the wheel guard40 during operation. The glide shoe 49 of the rail 50 constricts thecross section of the exit region of the wheel guard 40. This helps theair stream in the wheel guard 40 along in the direction toward the dustremoval tube 52.

As shown on the left side, a damping plate 76 is located next to thesanding disc/grinding wheel 28, which said damping plate extendsradially very close to the periphery of the sanding disc/grinding wheel28 and dampens a movement of air caused by the rotating sandingdisc/grinding wheel 28 during sanding. As a result, a certain vacuum isproduced inside the wheel guard 40, which said vacuum blows through thedust removal tube 52 and takes any sanding/grinding dust present alongwith it.

The collet 23 with the clamping nut for mounting the wheel guard 40 onthe gearbox housing 24 is shown. On the top, the wheel guard 40 iscovered horizontally with the pivoted cover plate 64 made of sheetmetal, attached to which said pivoted cover plate—as shown on the rightside—is a round, projecting swivel grip 65 to be operated using thethumb.

As shown on the left side, an arrow indicating the direction of rotationis stamped in the pivoted cover plate 64 that points to the left in theview shown. This is the intended direction of rotation for swiveling thepivoted cover plate 64 upward into its release position to remove thesanding disc/grinding wheel 28. Additionally, the arrow also indicatesthe direction of rotation of the sanding disc/grinding wheel 28. Thepivoted cover plate 64 is swung to the left by approximately 180° aroundthe center of rotation 42 so that the sanding disc/grinding wheel 28 canbe exposed and replaced after the retaining nut 27 is removed.

The frame segments 70 for accommodating the window 66 in thecorresponding opening are also clearly shown.

FIG. 14 shows the guide rule 60 as a fixed part of the wheel guard 40,relative to which the swiveling arm 38 can be adjusted via swiveling.The position of the swiveling arm 38 relative to the guide rule 60 canbe fixed and/or released using the knurled thumb screw 48a and/or usingthe knob 48 shown in FIGS. 1 through 4 by turning them around theiraxes.

The push button 63 of the depth-of-cut stop 62 can be engaged in thetoothed rack-like outer contour 59 by way of a mirror-image profile, andit can be disengaged with spring action by pressing on the push button63. If pressure on the push button 63 is released, it automaticallyengages with its mating profile 79 in the toothed rack-like outercontour 59 in the respective position. The depth-of-cut stop 62 can befixed in position at any position along the guide rule 60, so that theswiveling arm 38 with its knurled thumb screw 48 a can only be swiveledup to said stop. With this, a reproducible depth of cut is established.

FIG. 15 shows a detained view of the depth-of-cut stop 62 with its pushbutton 63 and a profile carrier 78 made of sheet metal that forms themating profile 79 for engaging in the toothed rack-like outer contour 59of the guide rule 60. A tab 80 is located on each of the opposite sidesof the profile carrier 78, which said tabs fit in the center slot 61 ofthe guide rule 60 for guided engagement. The profile carrier 78 ispenetrated transversely by a guide bolt 82, along which it can be movedtoward the push button 63 and away from said push button. The pushbutton 63 is preloaded elastically by means of a spiral-coiled spring83.

The push button 63 and the profile carrier 78 are securely bracedagainst each other, whereby, in the assembled state, the guide rule 60runs along between the two. The spiral-coil spring 83 with a supportdisc 84 comes to bear at the top against the guide rule 60 and, when thepush button 63 is operated, it moves in an axially spring-loaded fashionrelative to the guide rule 60, so that the profile carrier 78 with itsmating profile 79 can disengage from the outer contour 59 of the guiderule 60.

FIG. 16 shows a section of a spatial representation of the swivel grip65 of the pivoted cover plate 64. It is formed by part of the pivotedcover plate 64. As shown on the left, the pivoted cover plate 64comprises a tab 86 bent outwardly upward, through which a flexibletongue 88 of an L-shaped leaf spring 89 extends, which said leaf springis interconnected flatly with the rail 50, i.e., they are rivetedtogether in this case.

One of the frame segments 70 into which the window 66 can be inserted isshown at the top.

An opening 90 in the pivoted cover plate 64 is shown on the right side,which said opening snaps into place over a detent lobe 92 that extendsout of the adjacent side wall of the wheel guard 40. By swiveling thepivoted cover plate 64 to the right using the swivel grip 65 as viewedhere, the tab 86 can glide over the flexible tongue 88, and the opening90 can overcome the detent lobe 92, so that the pivoted cover plate 64can then be rotated around the center of rotation 42 (FIG. 13) withminimum force.

FIG. 17 shows an underside view of the wheel guard 40 with the top viewof the runner-like rail 50. Its surface forms a pass-through slot 73through which the not-shown sanding disc/grinding wheel 28 can enter andexit.

Shown at the bottom is the collet 23 with the pass-through opening 36for accommodating the neck 25 of the angle grinder 20 (FIG. 1). The legspring 58 is shown at the outer left, which said leg spring tries toswivel the swiveling arm 38 around the center of rotation 42, while thedust removal tube 52 projects in the lower right-hand side of thedrawing. The dust removal tube 52 tapers toward its mouth pointingtoward the sanding disc/grinding wheel 28. As a result, the conveyingair stream produced by the sanding disc/grinding wheel 28 flows rapidlyin the axial direction of the dust removal tube 52 through theconstriction in the mouth of the dust removal tube 52. It thereforeleaves the inside of the wheel guard 40 at great speed, whereby itexecutes the rotational motion described with FIG. 11. Due to thewidening of the dust removal tube in the direction away from the wheelguard 40, the air stream develops a suction effect due to its rotation,which said suction effect helps the air to exit the wheel guard andenter the dust removal tube 52.

The wheel guard 40 is covered on the top by the pivoted cover plate 64,the frame segments 70 of which project upwardly and hold the window 66.Additionally, the tab 86 is shown on the pivoted cover plate 64 at thetop right.

FIG. 18 shows a detained view of the stationary, shell-like side part 96of the wheel guard 40, to which the welded-on guide rule 60 is attachedas shown on the right.

The runner-like region of the rail 50 and the dust removal tube 52 canbe seen in the upper right. Shown particularly clearly here is thearrangement of the suction tube in the outermost corner of the wheelguard 40, at the site of origination of the sanding/grinding dust whenthe angle grinder 20 is used, through which said suction tube anysanding/grinding dust created moves by means of the high natural speedimparted by the sanding disc/grinding wheel 28 in conjunction with theblast air stream produced by the sanding disc/grinding wheel 28 itself.

Located approximately in the middle of the side part 96 is thepass-through opening 36, through which the neck 25 of the angle grinder20 extends. The pass-through opening 36 is a slot that allows the anglegrinder 20 and/or the neck 25 to swivel up and down relative to thewheel guard 40 until the maximum depth of cut is reached.

FIG. 19 shows the side part 96 as viewed from the inside, whereby therail 50, the dust removal tube 52, and the guide rule 60 are shownparticularly clearly. Moreover, the damper plate 76 and the observationopening 54 are shown on the outermost side of the side part 96.

FIG. 20 is a side view of the wheel guard 40 showing a section in theregion of the gearbox housing 24 of the angle grinder 20. Also shownclearly is the knob 48 for guiding the wheel guard 40 and/or foradjusting a preselected depth of cut and the depth-of-cut stop 62. Alsoshown is the dust removal tube 52, in the circumferential contour ofwhich the sanding disc/grinding wheel 28 passes through the opening 74with its radially outermost region.

Reference Numerals  20 Angle  22 Motor housing  23 Collet  24 Gearboxhousing  25 Neck  26 Drive shaft  27 Retaining nut  28 Sandingdisc/grinding wheel  29 Direction of rotation  30 Work piece  32 Groove 33 Guard device  34 Sliding button  36 Mounting opening  38 Swivelingarm  40 Wheel guard  42 Center of rotation  44 Guide slot  46 Giude bolt 48 Knob   48a Knurled thumb screw  49 Glide shoe  50 Rail  52 Dustremoval tube  54 Obervation opening  56 Handle  57 Advancing direction 58 Leg spring  59 Outer contour  60 Guide rule  61 Slot  62Depth-of-cut stop  63 Push button  64 Pivoted cover plate  65 Swivelgrip  66 Window  68 Air-intake opening  70 Frame segment  72 Snap-intongue  73 Pass-through slot  74 Opening  76 Damping plate  78 Profilecarrier  79 Mating profile  80 Tab  82 Guide bolt  83 Spiral-coiledspring  84 Support disc  86 Tab  88 Flexible tongue  89 Leaf spring  90Recess  92 Detent lobe  96 Side part 120 Angle grinder 122 Motor housing123 Collect 125 Neck 133 Guard device 138 Swiveling arm 140 Wheel guard148 Knurled nut 150 Rail 152 Dust removal tube 156 Handle 158 Leg spring162 Knurled nut 164 Pivoted cover plate 166 Window 167 Knurled nut 174Opening

1. A guard device (33) for a hand power tool, in the form of asanding/grinding hand power tool, comprising: a wheel guard (40)enclosing at least part of a rotating tool in a radial direction; aguide means for guiding the wheel guard (40) along a work piece (30),and comprising a fastening device for mounting the wheel guard (40) onthe hand power tool, wherein the guide means are joined with the wheelguard (40) in torsion-resistant fashion, and the wheel guard (40) ismounted in a fashion that allows it to move relative to the fasteningdevice; a depth-of-cut stop (62) limiting the relative movement of thewheel guard (40) and fastening device, and being lockable in positionwith positive engagement in preselected stepped positions; and means forforming a plurality of individual steps such that a part of saiddepth-of-cut is engageable into corresponding one of said individualsteps to be locked in said steps with positive engagement in saidpredetermined stepped positions.
 2. The guard device (33) according toclaim 1, wherein the guide means comprise at least one glide shoe (49).3. The guard device (33) according to claim 1, wherein the wheel guard(40) is mounted in a fashion that allows it to pivot relative to thefastening device.
 4. The guard device (33) according to claim 1, whereinthe wheel guard (40)—in a state in which it lies on a flat work piece(30) in the operating position—is provided to enclose the tool togetherwith the work piece (30) to an extent that is independent of thepenetration depth of the tool in the work piece (30).
 5. The guarddevice (33) according to claim 1, characterized by a spring mechanismthat presses the wheel guard (40) against a work piece (30) duringoperation.
 6. The guard device (33) according to claim 1, wherein thewheel guard (40), in the idle position, encloses the tool completely inthe axial direction.
 7. The guard device (33) according to claim 1,wherein the wheel guard (40) comprises two units capable of being movedrelative to each other that, in mutual interplay, comprise an operatingposition and a tool replacement position, whereby at least one of theunits, in the tool replacement position, exposes the tool in the axialdirection to an extent that allows a tool to be replaced.
 8. The guarddevice (33) according to claim 7, wherein the two units are capable ofbeing pivoted independent of each other around a common pivot (42)relative to the fastening device.
 9. The guard device (33) according toclaim 1, wherein the wheel guard (40)—in a state in which it lies on aflat work piece (30) in the operating position—comprises an air-intakeopening (68), the size of which is independent of the depth ofpenetration by the tool in the work piece (30).
 10. The guard device(33) according to 1, wherein the wheel guard (40) comprises a window(66) that ensures that the operator can see the tool.
 11. The guarddevice (33) according to claim 1, characterized by a dust removal tube(52).
 12. The guard device (33) according to claim 11, wherein the dustremoval tube (52) is mounted on the wheel guard (40).
 13. A hand powertool in the form of an angle grinder (20), comprising a guard device(33), wherein the guard device comprises a wheel guard (40) that isprovided to enclose at least part of a rotating tool in the radialdirection, and a guide means for guiding the wheel guard (40) along awork piece (30), and comprising a fastening device for mounting thewheel guard (40) on the hand power tool, wherein the guide means arejoined with the wheel guard (40) in torsion-resistant fashion, and thewheel guard (40) is mounted in a fashion that allows it to move relativeto the fastening device; a depth-of-cut stop (62) limiting the relativemovement of the wheel guard (40) and fastening device, and beinglockable in position with positive engagement in preselected steppedpositions; and means for forming a plurality of individual steps suchthat a part of said depth-of-cut stop is engageable into correspondingone of said individual steps to be locked in said steps with positiveengagement in said predetermined stepped positions.
 14. A guard device(33) for a hand power tool in the form of a sanding/grinding hand powertool, comprising: a wheel guard (40) enclosing at least part of arotating tool in a radial direction; guide means for guiding the wheelguard (40) along a work piece (30); a fastening device for mounting thewheel guard on the hand power tool, wherein the guide means are joinedwith the wheel guard (40) in a torsion-resistant fashion, and whereinthe wheel guard (40) is mounted in a fashion that allows it to moverelative to the fastening device, wherein the wheel guard (40) comprisesa window (66) that ensures that an operator can see the tool and whereinthe window (66) is made from a transparent material; a depth-of-cut stop(62) limiting the relative movement of the wheel guard (40) andfastening device, and being lockable in position with positiveengagement in preselected stepped positions; and means for forming aplurality of individual steps such that a part of said depth-of-cut stopis engageable into corresponding one of said individual steps to belocked in said steps with positive engagement in said predeterminedstepped positions.
 15. A guard device (33) for a hand power tool in theform of a sanding/grinding hand power tool, comprising: a wheel guard(40) enclosing at least part of a rotating tool in a radial direction;guide means for guiding the wheel guard (40) along a work piece (30); afastening device for mounting the wheel guard on the hand power tool,wherein the guide means are joined with the wheel guard (40) in atorsion-resistant fashion, wherein the wheel guard (40) is mounted in afashion that allows it to move relative to the fastening device, andwherein the wheel guard (40) comprises an observation silt orientatedtoward the narrow side of a sanding/grinding wheel; a depth-of-cut stop(62) limiting the relative movement of the wheel guard (40) andfastening device, and being lockable in position with positiveengagement in preselected stepped positions; and means for forming aplurality of individual steps such that a part of said depth-of-cut stopis engageable into corresponding one of said individual steps to belocked in said steps with positive engagement in said predeterminedstepped positions.
 16. A guard device (33) for a hand power tool in theform of a sanding/grinding hand power tool, comprising: a wheel guard(40) enclosing at least part of a rotating tool in a radial direction;guide means for guiding the wheel guard (40) along a work piece (30); afastening device for mounting the wheel guard on the hand power tool,wherein the guide means are joined with the wheel guard (40) in atorsion-resistant fashion, wherein the wheel guard is mounted in afashion that allows it to move relative to the fastening device; adamping plate formed inside the wheel guard by sheet material of thewheel guard and backing up air whirled by a rotating sanding/grindingwheel; a depth-of-cut stop (62) limiting the relative movement of thewheel guard (40) and fastening device, and being lockable in positionwith positive engagement in preselected stepped positions; and means forforming a plurality of individual steps such that a part of saiddepth-of-cut stop is engageable into corresponding one of saidindividual steps to be locked in said steps with positive engagement insaid predetermined stepped positions.
 17. A guard device (33) for a handpower tool in the form of a sanding/grinding hand power tool,comprising: a wheel guard (40) enclosing at least part of a rotatingtool in a radial direction; guide means for guiding the wheel guard (40)along a work piece (30); a fastening device for mounting the wheel guardon the hand power tool, wherein the guide means are joined with thewheel guard (40) in a torsion-resistant fashion, wherein the wheel guardis mounted in a fashion that allows it to move relative to the fasteningdevice, and wherein the fastening device and the wheel guard (40) areguided relative to one another by means of a guide bolt (46) seated onthe wheel guard (40) in a guide slot (44) of the fastening means; adepth-of-cut stop (62) limiting the relative movement of the wheel guard(40) and fastening device, and being lockable in position with positiveengagement in preselected stepped positions; and means for forming aplurality of individual steps such that a part of said depth-of-cut stopis engageable into corresponding one of said individual steps to belocked in said steps with positive engagement in said predeterminedstepped positions.
 18. A guard device (33) for a hand power tool in theform of a sanding/grinding hand power tool, comprising: a wheel guard(40) enclosing at least part of a rotating tool in a radial direction;guide means for guiding the wheel guard (40) along a work piece (30); afastening device for mounting the wheel guard on the hand power tool,wherein the guide means are joined with the wheel guard (40) in atorsion-resistant fashion, wherein the wheel guard (40) is mounted in afashion that allows it to move relative to the fastening device, andwherein a knob is mounted on the fastening device for guiding the powertool on a work piece; a depth-of-cut stop (62) limiting the relativemovement of the wheel guard (40) and fastening device, and beinglockable in position with positive engagement in preselected steppedpositions; and means for forming a plurality of individual steps suchthat a part of said depth-of-cut stop is engageable into correspondingone of said individual steps to be locked in said steps with positiveengagement in said predetermined stepped positions.